1/* SPDX-License-Identifier: GPL-2.0 */ 2#ifndef _ASM_X86_NOPS_H 3#define _ASM_X86_NOPS_H 4 5/* 6 * Define nops for use with alternative() and for tracing. 7 * 8 * *_NOP5_ATOMIC must be a single instruction. 9 */ 10 11#define NOP_DS_PREFIX 0x3e 12 13/* generic versions from gas 14 1: nop 15 the following instructions are NOT nops in 64-bit mode, 16 for 64-bit mode use K8 or P6 nops instead 17 2: movl %esi,%esi 18 3: leal 0x00(%esi),%esi 19 4: leal 0x00(,%esi,1),%esi 20 6: leal 0x00000000(%esi),%esi 21 7: leal 0x00000000(,%esi,1),%esi 22*/ 23#define GENERIC_NOP1 0x90 24#define GENERIC_NOP2 0x89,0xf6 25#define GENERIC_NOP3 0x8d,0x76,0x00 26#define GENERIC_NOP4 0x8d,0x74,0x26,0x00 27#define GENERIC_NOP5 GENERIC_NOP1,GENERIC_NOP4 28#define GENERIC_NOP6 0x8d,0xb6,0x00,0x00,0x00,0x00 29#define GENERIC_NOP7 0x8d,0xb4,0x26,0x00,0x00,0x00,0x00 30#define GENERIC_NOP8 GENERIC_NOP1,GENERIC_NOP7 31#define GENERIC_NOP5_ATOMIC NOP_DS_PREFIX,GENERIC_NOP4 32 33/* Opteron 64bit nops 34 1: nop 35 2: osp nop 36 3: osp osp nop 37 4: osp osp osp nop 38*/ 39#define K8_NOP1 GENERIC_NOP1 40#define K8_NOP2 0x66,K8_NOP1 41#define K8_NOP3 0x66,K8_NOP2 42#define K8_NOP4 0x66,K8_NOP3 43#define K8_NOP5 K8_NOP3,K8_NOP2 44#define K8_NOP6 K8_NOP3,K8_NOP3 45#define K8_NOP7 K8_NOP4,K8_NOP3 46#define K8_NOP8 K8_NOP4,K8_NOP4 47#define K8_NOP5_ATOMIC 0x66,K8_NOP4 48 49/* K7 nops 50 uses eax dependencies (arbitrary choice) 51 1: nop 52 2: movl %eax,%eax 53 3: leal (,%eax,1),%eax 54 4: leal 0x00(,%eax,1),%eax 55 6: leal 0x00000000(%eax),%eax 56 7: leal 0x00000000(,%eax,1),%eax 57*/ 58#define K7_NOP1 GENERIC_NOP1 59#define K7_NOP2 0x8b,0xc0 60#define K7_NOP3 0x8d,0x04,0x20 61#define K7_NOP4 0x8d,0x44,0x20,0x00 62#define K7_NOP5 K7_NOP4,K7_NOP1 63#define K7_NOP6 0x8d,0x80,0,0,0,0 64#define K7_NOP7 0x8D,0x04,0x05,0,0,0,0 65#define K7_NOP8 K7_NOP7,K7_NOP1 66#define K7_NOP5_ATOMIC NOP_DS_PREFIX,K7_NOP4 67 68/* P6 nops 69 uses eax dependencies (Intel-recommended choice) 70 1: nop 71 2: osp nop 72 3: nopl (%eax) 73 4: nopl 0x00(%eax) 74 5: nopl 0x00(%eax,%eax,1) 75 6: osp nopl 0x00(%eax,%eax,1) 76 7: nopl 0x00000000(%eax) 77 8: nopl 0x00000000(%eax,%eax,1) 78 Note: All the above are assumed to be a single instruction. 79 There is kernel code that depends on this. 80*/ 81#define P6_NOP1 GENERIC_NOP1 82#define P6_NOP2 0x66,0x90 83#define P6_NOP3 0x0f,0x1f,0x00 84#define P6_NOP4 0x0f,0x1f,0x40,0 85#define P6_NOP5 0x0f,0x1f,0x44,0x00,0 86#define P6_NOP6 0x66,0x0f,0x1f,0x44,0x00,0 87#define P6_NOP7 0x0f,0x1f,0x80,0,0,0,0 88#define P6_NOP8 0x0f,0x1f,0x84,0x00,0,0,0,0 89#define P6_NOP5_ATOMIC P6_NOP5 90 91#ifdef __ASSEMBLY__ 92#define _ASM_MK_NOP(x) .byte x 93#else 94#define _ASM_MK_NOP(x) ".byte " __stringify(x) "\n" 95#endif 96 97#if defined(CONFIG_MK7) 98#define ASM_NOP1 _ASM_MK_NOP(K7_NOP1) 99#define ASM_NOP2 _ASM_MK_NOP(K7_NOP2) 100#define ASM_NOP3 _ASM_MK_NOP(K7_NOP3) 101#define ASM_NOP4 _ASM_MK_NOP(K7_NOP4) 102#define ASM_NOP5 _ASM_MK_NOP(K7_NOP5) 103#define ASM_NOP6 _ASM_MK_NOP(K7_NOP6) 104#define ASM_NOP7 _ASM_MK_NOP(K7_NOP7) 105#define ASM_NOP8 _ASM_MK_NOP(K7_NOP8) 106#define ASM_NOP5_ATOMIC _ASM_MK_NOP(K7_NOP5_ATOMIC) 107#elif defined(CONFIG_X86_P6_NOP) 108#define ASM_NOP1 _ASM_MK_NOP(P6_NOP1) 109#define ASM_NOP2 _ASM_MK_NOP(P6_NOP2) 110#define ASM_NOP3 _ASM_MK_NOP(P6_NOP3) 111#define ASM_NOP4 _ASM_MK_NOP(P6_NOP4) 112#define ASM_NOP5 _ASM_MK_NOP(P6_NOP5) 113#define ASM_NOP6 _ASM_MK_NOP(P6_NOP6) 114#define ASM_NOP7 _ASM_MK_NOP(P6_NOP7) 115#define ASM_NOP8 _ASM_MK_NOP(P6_NOP8) 116#define ASM_NOP5_ATOMIC _ASM_MK_NOP(P6_NOP5_ATOMIC) 117#elif defined(CONFIG_X86_64) 118#define ASM_NOP1 _ASM_MK_NOP(K8_NOP1) 119#define ASM_NOP2 _ASM_MK_NOP(K8_NOP2) 120#define ASM_NOP3 _ASM_MK_NOP(K8_NOP3) 121#define ASM_NOP4 _ASM_MK_NOP(K8_NOP4) 122#define ASM_NOP5 _ASM_MK_NOP(K8_NOP5) 123#define ASM_NOP6 _ASM_MK_NOP(K8_NOP6) 124#define ASM_NOP7 _ASM_MK_NOP(K8_NOP7) 125#define ASM_NOP8 _ASM_MK_NOP(K8_NOP8) 126#define ASM_NOP5_ATOMIC _ASM_MK_NOP(K8_NOP5_ATOMIC) 127#else 128#define ASM_NOP1 _ASM_MK_NOP(GENERIC_NOP1) 129#define ASM_NOP2 _ASM_MK_NOP(GENERIC_NOP2) 130#define ASM_NOP3 _ASM_MK_NOP(GENERIC_NOP3) 131#define ASM_NOP4 _ASM_MK_NOP(GENERIC_NOP4) 132#define ASM_NOP5 _ASM_MK_NOP(GENERIC_NOP5) 133#define ASM_NOP6 _ASM_MK_NOP(GENERIC_NOP6) 134#define ASM_NOP7 _ASM_MK_NOP(GENERIC_NOP7) 135#define ASM_NOP8 _ASM_MK_NOP(GENERIC_NOP8) 136#define ASM_NOP5_ATOMIC _ASM_MK_NOP(GENERIC_NOP5_ATOMIC) 137#endif 138 139#define ASM_NOP_MAX 8 140#define NOP_ATOMIC5 (ASM_NOP_MAX+1) /* Entry for the 5-byte atomic NOP */ 141 142#ifndef __ASSEMBLY__ 143extern const unsigned char * const *ideal_nops; 144extern void arch_init_ideal_nops(void); 145#endif 146 147#endif /* _ASM_X86_NOPS_H */ 148